Core chuck



Nov. 25, 1969 AR 3,480,224

CORE CHUCK Filed Feb. 21. 1968 //vvr0,-?. MERLIN a. CLARK 50" I EH 5.

United States Patent O US. Cl. 24268.2 9 Claims ABSTRACT OF THE DISCLOSURE The core chuck includes an eccentric ring carried on an eccentric hub member and adapted to be rotated into a position whereby the outer circumferential surface of the eccentric ring is brought into binding frictional contact with the inside of the core. By these means a driving engagement is had without distortion of the supported end of the core. The core chuck is further characterized by the eccentric ring having an outside diameter sealed for concentric sliding engagement within the core, when in retracted position, whereby frictional engagement with the inner core surface rotates the ring eccentrically relative to the core axis and into binding engagement with the core.

BACKGROUND OF THE INVENTION Chucks are used for mounting hollow cylindrical cores on a drive shaft whereby elongated sheet material can be wound upon the core or unwound therefrom. In the past, the fixation of the core to the shaft has been a problem because of the necessarily fragile and resilient nature of the cores used, namely pressed cardboard, paper, plastics and the like. One form of prior 'art chuck comprises a tapered member which is driven into the open end of the core with a wedging action. This invariably results in distortion of the end of the core and a similar distortion of the margin of the material being wound onto the core. In many instances, such as in the winding of wrapping paper, or sheet plastic material, the marginal edges are spoiled. Any enlargement of the ends of the core also tends to adversely influence the straightness with which the sheet material can be wound onto the core. Also any distortion of the core ends can cause difliculties where the core is to be used subsequently on the same or different chuck and shaft combination during the unwinding of the sheet material, as in feeding the roll into a printing, dyeing or trimming operation. In some operations special precautions must be taken to avoid any expansion of the core ends. The forces required to both wind and unwind sheet material from a core are considerable, particularly in the paper-making industry and the like where the rolls may weigh one or more' tons and be processed at high speeds of rotation. The instant invention is directed to a core chuck which overcomes these and related difficulties in this art.

SUMMARY OF THE INVENTION Accordingly, the instant invention concerns a core chuck that can be inserted into the end of a hollow core and be expanded radially over a sufficient area to provide a frictional grip upon the core without any danger of expanding the outside diameter of the core adjacent the chuck. The core chuck of this invention includes an eccentric ring carried on an eccentric hub wherein the outer surface of the ring is equally spaced about the center of the supporting shaft and rotation of the ring on the hub moves the outer surface of the ring into binding engagement with the surface of the bore hole in the core end and thus provides a lock-fit with no distortion. This invention is further characterized by its adaptation for accomplishing the rotation of the eccentric ring into driving engagement with the core merely through sliding frictional contact with the inner surface of the core. In one embodiment a separable collar on the extended outer end of the hub serves to position the chuck in the end of the core and in another embodiment the chuck is positioned in the core end by means of retractable radially projecting pins on the outer end of the chuck. Means are provided in the form of a set screw to lock the separable collar and the chuck hub onto the supporting shaft. The core chuck of this invention is readily manufactured, low in cost, has essentially no wearing parts and is easily used.

DESCRIPTION OF THE DRAWINGS Specific and non-limiting embodiments of this invention are illustrated by the drawings wherein:

FIG. 1 is a side view of a core engaged by end chucks according to this invention, the supporting shaft being cut away at the ends;

FIG. 2 is an enlarged end view, from the plane 22, of the embodiment shown in FIGS. 1 and 3 with a portion cut away to show the manner of attachment of the hub to the shaft;

FIG. 3 is a fragmentary cross-sectional view taken along the lines 33 of FIG. 1;

FIG. 4 is a cross-sectional view as taken along the lines 4-4 of FIG. 3;

FIG. 5 is a cross-sectional view of a modified form of the eccentric ring chuck of this invention for the end of the assembly of FIG. 1 over which the core is positioned on and removed from the supporting shaft.

FIG. 6 is a fragmentary end view of a preferred form of the eccentric ring; and

FIG. 7 is a fragmentary cross-sectional view similar to FIG. 3, but in reduced size, to show another form of the chuck hub and positioning collar "for use in combination with the eccentric locking ring of this invention.

THE PREFERRED EMBODIMENT Referring to the drawings, FIG. 1 shows a core mounted roll of material 10 carried on the shaft 12 and engaged between a pair of positioning collars carried on respective chucks 1414. In FIG. 3 the relationship of these parts is more clearly shown wherein the material 10 is wound upon the elongated cylindrical member or core 16 and a sleeve or hub member 18, slidable on the shaft 12 and having an integral radial inner flange 20, is inserted within the central bore 22 of the core 16'. The outer diameter of the flange 20 is slightly less than the inner diameter of the bore 22 so that there is a free sliding clearance 24 therearound. This allows the hub 18 to be readily received into the open end of the core.

The hub 18 has a bore 26 extending concentrically from the outer cylindrical portion 28 through to the flange '20 in a sliding fit relationship on the shaft 12 with little if any radial play between these parts. The shaft 12 may be a driven or drive shaft and it is convenient to be able to move the hub 18 along the shaft to a desired position for any particular core length before the chuck is tightened. The outer surface 30 of the cylindrical portion 28 is likewise concentric with the shaft 12. In order that the hub 18 can be made to rotate with the shaft 12 a threaded radial bore 32 is provided to receive the Allen screw 34 in order to lock the hub to the shaft. Instead of the Allen screw the hub 18 can be keyed to the shaft 12, or any other suitable means of releasably affixing the hub and shaft can be used.

Between the cylindrical portion 28 and the concentric flange 20 the hub 18 has an eccentric cylindrical lobe 40 which has its axis radially off-set from the axis of the hub. This forms an eccentric annular space 42 between the lobe 40 and the inner circular surface 44 of the core 16. Within this annular space 42 there is con tained the eccentric ring 50 having a bore of substantially the same diameter as the lobe 40 and the same eccentricity thus providing a portion 52 of greater radial thickness than the portion 54. The ring 50 is made with an outside diameter such as to provide a frictional sliding fit in the core 16 when in the position concentric with the flange 20, as shown in FIG. 4. The ring 50 engages the lobe 40 in a free rotational fit and if desired the opposed surfaces or juncture 56 can have a thin film of lubricant thereon.

Rotation of the ring 50 is caused by rotation of the core 16 relative to the chuck and the frictional drag of the core on the outer surface of the ring 50. One treatment of the outer surface of the ring 50 to assure frictional drag of the ring 50 by rotation of the core 16 on the chuck and subsequent driving engagement of the ring with the core is shown in FIG. 6 where the ring is provided with axially extending ribs 58. Other means for enhancing frictional engagement of the ring 50 and the inner surface of the core may be employed if desired. For example, a rubber coating or any other suitable means for treating the outer periphery of the ring may be used.

As shown, a positioning ring 60 is mounted on the hub portion 28, of the chuck form shown in FIG. 3, to serve the dual function of holding the eccentric ring 52 in place on the lobe 40 and also serving as a stop means to limit insertion of the chuck into the core 16 and to position the web of material wound onto the core. In order to secure the positioning ring 60 on the hub portion 28, the ring 60 is provided with threaded radial bores 64, having the same angular spacing as the bores 32 in the hub portion 28, and the set screw 34 is of sufficient length to extend from the shaft 12 well into the ring 60, as shown in FIGS. 2 and 3.

It will now be apparent that when a core is applied over the chuck 14, into engagement with the positioning ring 60, it will frictionally engage the eccentric ring 50 and cause it to rotate on the lobe 40 of the chuck hu-b upon relative rotation of the chuck and core. Such turning of the ring 50, about the eccentric axis of its bore and with respect to the lobe 40, will cause the ring to become eccentric relative to the axis of the core and bring the outer periphery of the thicker portion 52 of the ring into binding and driving engagement with the core, thus effectively expanding the chuck radially but only to the extent, governed by the core itself, necessary to drive the core through rotation of the shaft 12.

In order that as large an area of the eccentric ring 50 will engage the inner surface of the core 16, when in driving relation, the eccentricity of the ring bore and the hub lobe 40 is made to be quite small, for example inch or less from the axis of the chuck and the shaft 12, as indicated at C-C' in FIG. 4 where C is the eccentric axis. Also the outside diameter of the eccentric ring 50 preferably will be within the range of to- & inch less than the inside diameter of the core 16. The diameter of the flange 20 will be about the same as that of the ring 50 in order to provide support for the core well within the core end.

As shown in FIG. 5 the core chuck 14', for the other end of the core 16, is made to permit the core to be applied to or removed from the shaft 12 without removing one or the other of the chucks. In this case the positioning ring 66 is made with the same outside diameter as the flange 20, so as to readily slide into the core and also provide support for the core. The positioning ring 66 has threaded radial bores, for alignment with the bores 32' in the hub portion 28', for reception of set screws 34' as in the case of the chuck 14 and the chuck 14' is thereby secured on the shaft 12.

The hub lobe 40', the eccentric ring 50', and the flange of the chuck 14 are the same as in the opposite end chuck 14. The flange 20', however, is provided with a plurality of retractable positioning pins 68 which are spring actuated to project radially from the flange 20. These positioning pins 68 are angularly spaced about the periphery of the flange 20', to engage the end of the core 16 and limit its axial movement relative to the shaft 12. For removal of the core 16, over the chuck 14', the pins 68 are manually depressed until the core 16 is sufliciently withdrawn to hold them down. Each of the pins 68 is mounted in a suitable bore 70 in the flange 20, of sufficient depth to include a spring 72 which normally urges the pin outwardly and to permit the pin to be depressed flush with the surface of the flange 20'.

A modified form of chuck in accordance with this invention is shown in FIG. 7. In this embodiment the hub 18' is extended axially so that the cylindrical sleeve portion is elongated while retaining the eccentric lobe 40", the eccentric ring 50" and the flange 20" are of essentially the same form as shown in FIGS. 2 and 3 for insertion within the core 16. The positioning collar 92 is then modified by providing a sleeve portion 94, integral therewith, which extends over the longer cylindrical sleeve portion 90 and well into the interior of the core and like the flange 20" provides support for the end of the core 16. This arrangement places the eccentric ring 50 inwardly of the open end of the core 16 and, in the case of relatively thin walled cores, minimizes any likelihood of the core being distorted.

The core chuck of this invention may be variously modified within the scope of the appended claims. The size of the parts may be varied. A ring lock core chuck according to this invention can be made of various sizes to accommodate cores having inside diameters of 2 to 6 inches, for example, and shaft sizes of 1% to 2 inches or more. The parts are constructed of steel so as to withstand hard uses, although the invention is not to be limited to the type of construction materials used, and in some applications plastic parts can be used.

Preferably the eccentric surfaces are circular. The center C, see FIG. 4, is the center of the shaft 12, the hub portion 28, the flange 20, and the core 16, while the center C' is the rotational center for the eccentric lobe 40 and the bore of the ring 50.

Having thus described one or more specific embodiments of this invention, it will be understood that the details of construction and operation shown can be altered or omitted without departing from the spirit of the invention as defined by the appended claims.

I claim:

1, A chuck adapted to engage within the annular opening between a hollow cylindrical member and a supporting shaft of lesser diameter than said hollow member, said chuck comprising (a) a sleeve member adapted to fit within said annular opening,

(b) an eccentric annular surface formed on said sleeve; and

(c) a rotatable ring having a sliding fit within the cylindrical member and an eccentric bore encompassing said eccentric surface,

(d) said cylindrical member having frictional engagement with said ring so as to rotate said ring on said eccentric surface whereby a portion of the periphery of said ring is brought radially into driving frictional engagement with said cylindrical member.

2. A chuck in accordance with claim 1 in which (a) said eccentric surface is annular with its center off-set from the center of said sleeve member, and

(b) said eccentric ring is annnular with its bore center coincident with the center of said sleeve.

3. A chuck according to claim 1 wherein the eccentric surface comprises an annular portion of the sleeve member intermediate the ends thereof and radially offset from the sleeve axis.

4. A chuck in accordance with claim 1 in which (a) said sleeve has a radial flange at one end having a diameter of a size to provide a sliding fit within the annular opening of said cylindrical member.

5. A chuck according to claim 1 wherein the sleeve member is provided with a radial flange at one end and a removable collar at its other end and said eccentric sur- 5 face and said ring are disposed between the radial flange and said removable collar.

6. A chuck according to claim 1 wherein one end of the sleeve member has a radial flange having an outside diameter substantially equal to the outside diameter of the said ring, and a removable collar of greater diameter than said ring is mounted on the opposite end of the sleeve member, said ring being disposed between said collar and said flange.

7. A chuck according to claim 4 wherein said flange has a retractable pin mounted therein and projecting radially outward therefrom.

8. A chuck according to claim 4 wherein said flange has a plurality of angularly spaced retractable pins mounted therein and normally projecting radially therefrom, each of said pins being radially retractable into a radial socket in said flange, and means are provided for normally urging said pins radially outward from their respective sockets.

9. A chuck according to claim 5 wherein said flange has a radially projecting pin disposed in a radial Socket in the References Cited UNITED STATES PATENTS Hunter 242-72 Bandy 242-72 Cummings 242-683 'Field 242-683 Wright 242--68.2

20 NATHAN L. MINTZ, Primary Examiner 

